There have been a lot of cheap Chinese tablet using the same SoC, and usually they come with Android/Windows dualboot. So what's preventing us from running Sailfish OS on them? Android firmware can often be easily ported between such devices, but kernel is device-specific, so custom ROM makers just use the stock kernel from their device unmodified.

For Sailfish OS, we can't, since systemd requires some kernel options which are most of time turned off in Android kernels. Enabling them and recompiling kernel would be easy if Chinese manufacturers didn't violate GPL and actually provided kernel sources, but that's not the case. Thankfully, since most of hardware is similar, it's possible to base custom kernel on other device source.

I have Sailfish OS running on Onda V820w tablet. It's not perfect yet, but the hardware itself (touchscreen, audio, Wi-Fi, Bluetooth, front and back cameras) works. Many thanks to Stskeeps for providing modules folders which were missing from Jolla Tablet kernel sources. The biggest problem was getting kernel working with camera sensors. Even though the needed drivers are present, PMIC regs and GPIO pin meanings turned out to be different. Just a few values to change, but it was very troublesome to debug and I had to disassemble Onda stock Android kernel to understand what's wrong.

Below is a guide to installing Sailfish OS on Onda V820w (tested with V3, see serial number to understand what revision is yours if you happen to have it). Hope community will be interested in running Sailfish OS on other similar devices and we can have more supported. I'm happy to help with what I can either here or at #sailfishos-porters on IRC.

1. Make ext4 partition at least 2 GiB large on your microSD card. GParted is your friend in this. It's also possible to use internal NAND, but this would require booting Linux LiveCD on tablet for partitioning, using microSD is easier and safer for testing.

2. You can either download Jolla Tablet firmware yourself and extract root/home partition. On Jolla Tablet LVM is used with separate partitions for root, /home and /fimage (recovery images). I didn't use this structure since it complicates testing and amount of available space on tablet is pretty low, and instead moved /home contents on root partition. /fimage is not needed since we don't have recovery images anyway. Then overwrite the contents of root partition with the contents of "root" folder from https://github.com/NotKit/sailfishos-onda-v820w-overlay.

3. Now you need to adjust the contents of grub.cfg in /boot.
root= should to point to the right partition, /dev/mmcblk1p2 by default for second partition on microSD card.
Since the tablet can't boot from SD card, we need to copy bzImage, grubia32.efi and grub.cfg from /boot to the root of internal NAND ESP partition. If you have root access in Android, you can mount it like this:

Code:

su
mkdir /data/local/esp
mount -t vfat /dev/mmcblk0p1 /data/local/esp

4. Connect USB keyboard and reboot the tablet, holding Esc key. It should go to the boot menu. Select "Boot From File" option and chose ESP partition in the list, then launch grubia32.efi.

The first option in GRUB should normally boot Sailfish OS. First boot is going to take around a minute, but If you have black screen for too long, try pressing power button.

The second (init-debug) enables USB networking and telnet daemon as specified in 9.2 of HADK porting guide. It halts booting until you connect via telnet and tell it to continue, so don't expect anything but black screen until then.

Hi, sorry for replying so late, but this really caught my attention as it could be a cheaper alternative to the Jolla Tablet. First, I want to thank you for the detailed tutorial and for the effort.

Would you (or anyone else with this tablet) please be willing to share any experience with using it for a few weeks?

What about the battery life? How much power does it draw when idle?
Does the miniHDMI-out work?

And the final question - since the port is based on the Jolla Tablet files (if I understand it correctly) and it uses the same kernel version, do the proprietary parts of SailfishOS work as well? Namely Alien Dalvik, Jolla Store and MS Exchange (never used it, but I'm curious).

Thanks.

__________________I don't understand why would anyone use a random, insecure, proprietary chatting solution as WhatsApp, when you have so many safe and open alternatives.
Please, don't use it. If this doesn't convince you, read more here.
The worst thing is even if you don't use it, it takes one ***** who does and has your number in his/her contacts and your number is uploaded to servers of this insane company for 'anyone interested' to read.
Thumbs up for everyone supporting WhatsApp on Maemo. NOT

Hi, sorry for replying so late, but this really caught my attention as it could be a cheaper alternative to the Jolla Tablet. First, I want to thank you for the detailed tutorial and for the effort.

Would you (or anyone else with this tablet) please be willing to share any experience with using it for a few weeks?

What about the battery life? How much power does it draw when idle?
Does the miniHDMI-out work?

And the final question - since the port is based on the Jolla Tablet files (if I understand it correctly) and it uses the same kernel version, do the proprietary parts of SailfishOS work as well? Namely Alien Dalvik, Jolla Store and MS Exchange (never used it, but I'm curious).

Thanks.

Unfortunately, I was more interested in getting SailfishOS running on it than actually using the device, so can't really share much user experience. Battery should be around 3 hours for general use. miniHDMI is untested, since I don't have a display to plug it in, but it probably won't work, since Sailfish OS doesn't support more than one screen so far and they purposefully shipped Jolla Tablet without HDMI port.

As for the device itself, build quality/official OS (Windows/Android I mean) support/etc is not to be compared with more expensive devices, but it still does a lot for the price in terms of hardware itself.

And for the last question, yes, but it probably goes against the rules.

Originally Posted by deutch1976

Hi there
Also interested for my Toshiba Encore WT8-A-103

Since your device doesn't have official Android firmware, libhybris can't be used, but pure Linux adaptation will be probably much more generic. You can try running latest build of Remix OS and Android-x86 itself (they've integrated many kernel patches for Bay Trail) or general Linux distro to see what in terms of hardware support is likely to work and what's not.